Effect of ratios of Li2MnO3 and Li(Ni1/3Mn1/3Co1/3)O2 phases on structure and electrochemical properties of xLi2MnO3·(1-x)LiMn1/3Co1/3Ni1/3O2 cathode materials
Abstract
A series of xLi2MnO3·(1-x)LiMn1/3Ni1/3Co1/3O2 cathode materials were successfully prepared by sol-gel method. The effect of different contents of two components on the structure, morphology and electrochemical properties of the prepared materials were intensively investigated through X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge tests. The results showed that all the prepared lithium rich manganese based cathode materials with different components had reasonable layered structure and the electrochemical performance of the materials were affected by the proportion of two phase components. For x=0.5, the material had the highest initial discharge specific capacity of 280.9 mAh·g-1 at 0.1C and the initial efficiency was 83.1%. After 50 cycles of 0.5C, the highest discharge specific capacity was 207.80 mAh·g-1 with the capacity retention rate of 84.2%. Besides, the material had batter rate performance (148.6mAh•g-1 , 5C) and lower charge transfer impedance.
